| Organization (Details 2) (Corporate Office Properties, L.P.) | 3 Months Ended | 
|---|---|
| Mar. 31, 2014
 Trustee | |
| Common Units | |
| Forms of ownership in Operating Partnership and ownership percentage by the entity | |
| Percentage ownership in operating partnership | 95.70% | 
| Number of trustees controlling additional common units | 3 | 
| Additional percentage of common units controlled by trustees (as a percent) | 3.40% | 
| Preferred Units | |
| Forms of ownership in Operating Partnership and ownership percentage by the entity | |
| Percentage ownership in operating partnership | 96.40% | 
| X | ||||||||||
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- Definition Additional percentage of the operating partnership's common units controlled by trustees, either directly or through ownership by other entities or family members. No definition available. 
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| X | ||||||||||
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- Definition Represents the number of trustees who control common units in addition to those owned by the entity. No definition available. 
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| X | ||||||||||
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- Details 
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| X | ||||||||||
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- Definition Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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